The best gift my LO (just turned 3 years old) can give to me for my birthday is puking all over his bed just now

This happens once every winter, why?

He has started saying he had a stomachache at bedtime. Then got up to poop once, and then vomited everywhere an hour later. He said he is still not feeling well I couldn't give him anything because I don't want him to throw up again for at least an hour.

Since I am not going to call the nurse on call, can someone give me a refresh course on what to do when he pukes to avoid dehydration? I remember the nurse said no fluid for at least an hour, and then one teaspoon of water/electrolyte every 30 (?) minutes, then 15 mins, then 10 mins...etc. and gradually increase dosage. Keep him on diet of toast, banana, apple sauce, and rice... what else again?

Anything else I forgot? Anything I could do to make him feel better?

Thank you Bees!